1. Field of the Invention
The present invention relates to a slide cylinder device which reciprocatively moves a moving board in accordance with reciprocatory movement of a cylinder, the moving board being loaded with a goods catch and take-off carrying means like robots hands.
2. Description of the Prior Art
As shown in FIGS. 5, 6, there has heretofore been well known a slide cylinder device in which a cylinder 100 is so provided as to be reciprocatively movable along a piston rod 101 passing through the cylinder 100 and extending therefrom. A moving board 103 is so provided as to be reciprocatively movable. The moving board 103 is guided by guide rails 102 disposed in parallel with the piston rod 101. There is formed a frame 104 including standing walls 104a, 104b which supportingly fix the respective ends of the piston rod 101 as well as the guide rails 102, the standing walls 104a, 104b being provided at both ends in the longitudinal direction thereof. Movement end portions of flexible linkage members 105A, 105B are linked to the moving board 103 and proximal ends thereof are linked to the front and rear standing walls 104a, 104b of the frame 104. The flexible linkage members 105A, 105B are spanned between a pair of movable pulleys 106A, 106B secured to the cylinder 100.
The slide cylinder device of this type is constituted such that a fluid (for instance, air) is sent alternately from passages 101a, 101b formed in the piston rod 101 into the cylinder 100 thereby to reciprocatively move the cylinder 100 with the guide of the piston rod 101. This movement is conveyed via the flexible linkage members 105A, 105B to the moving board 103 in order that the moving board 103 makes a reciprocatory movement that is twice as long as the movement of the above-described cylinder 100 in the same direction thereof while being guided by the guide rails 102.
In the conventional slide cylinder device, the flexible linkage members 105A, 105B are stretched between only the movable pulleys secured to the cylinder 100. This configuration, however, creates the following disadvantages. If a member (such as robot-hands) is interposed between the cylinder 100 and the moving board 103, this member interferes with the moving board 103 and the flexible linkage members 105A, 105B when the cylinder 100 and the moving board 103 are operated, thereby bringing about an incapability in terms of operation.
For this reason, a cross-sectional configuration of the frame 104 itself inevitably becomes a substantially U-shape whose opening is formed on the side of the moving board 103 as shown in FIG. 7. Such a cross-sectional configuration, however, involves a defect wherein the frame, 104 is low in rigidity. A large decrease in torsional rigidity occurs especially with the long-sized frame which allows a large amount of stroke with respect to the cylinder 100 and the moving board 103.
The torsional rigidity of the frame 104 is lowered, and the torsion is created in the frame 104 at the time of operation, which leads to a disadvantage such that it becomes unfeasible to reciprocatively move the moving board 103 even if the cylinder makes a reciprocatory movement due to a deteriorated condition of the flexible linkage members 105A, 105B spanning the movable pulleys 106A, 106B.
Hence, it is required to enhancing the torsional rigidity of the frame 104 by reinforcing the frame, and inevitably the frame 104 becomes intricate. Furthermore, this causes an increase in amount of processing. On the other hand, dust entering the inside portion from the upward opening adheres to the piston rod 101 and infiltrates into a sealing portion 100a. This produces problems in which the sealing portion 100a is worn off in a relatively short time thereby to degrade sealing properties of the cylinder 100.